User talk:Patricia Barden

Overview
Coal mining and coal combustion in power plants produce several types of wastes:
 * The mining process itself produces waste coal or solid mining refuse, which is a mixture of coal and rock.
 * The mining process also produces liquid coal waste, which is then stored in impoundments.
 * Pollution control equipment used for coal combustion produces coal ash or fly ash, as well as flue-gas desulfurization (FGD), a wet solid residue created by sulfur dioxide scrubbers.

Waste coal
According to the Department of Energy, waste coal is "Usable material that is a byproduct of previous coal processing operations. Waste coal is usually composed of mixed coal, soil, and rock (mine waste).  Most waste coal is burned as-is in unconventional fluidized-bed combustors.  For some uses, waste coal may be partially cleaned by removing some extraneous noncombustible constituents.  Examples of waste coal include fine coal, coal obtained from a refuse bank or slurry dam, anthracite culm, bituminous gob, and lignite waste." Waste coal is referred to as "culm" in the Eastern Pennsylvania anthracite fields and as "gob" or "boney" in the bituminous coal mining regions.

Liquid coal waste
Before burning, coal is crushed and washed, creating waste water filled with toxins. Another form of liquid coal waste is acidic mine runoff. Both forms of liquid coal waste are disposed of in a landfill at the mine site. Each year coal preparation creates waste water containing an estimated 13 tons of mercury, 3236 tons of arsenic, 189 tons of beryllium, 251 tons of cadmium, and 2754 tons of nickel, and 1098 tons of selenium.

Coal ash and scrubber sludge
The 1.05 billion tons of coal burned each year in the United States contain 109 tons of mercury, 7884 tons of arsenic, 1167 tons of beryllium, 750 tons of cadmium, 8810 tons of chromium, 9339 tons of nickel, and 2587 tons of selenium. On top of emitting 1.9 billion tons of carbon dioxide each year, coal-fired power plants in the United States also create 120 million tons of toxic waste. That means each of the nation's 500 coal-fired power plants produces an average 240,000 tons of toxic waste each year. A power plant that operates for 40 years will leave behind 9.6 million tons of toxic waste.